GPS Users Positioning Errors during Disturbed Near-Earth Space Conditions

摘要

Operation quality of the Global Navigation Satellite Systems (GNSS) appreciably depends on condition of the near-Earth space environment. Afraimovich et al. (GPS Solutions, 2003, V7, N2, 109) showed, that during geomagnetic disturbances in the near space deterioration of GNSS operation quality is appeared and, as consequence, reduction of positioning accuracy and occurrence of failures in definition of ground based users coordinates are observed. Application of GNSS for the decision of orbital objects navigation tasks allows to increase considerably accuracy of coordinates and parameters of movement definition of such objects. Wickert et al. (J. Communications Technology and Electronics, 2004, V49, N10, 1184) found strong amplitude and phase fluctuations of L-band radio waves on line-of-sight satellite-to- satellite . However from the viewpoint of GNSS users research of positioning accuracy is of much greater interest. The aim of our research is estimation of GPS ground and orbital users positioning accuracy in different geomagnetic conditions. Interrelation between total electron content (TEC) variations and positioning accuracy during the strong magnetic storms on 29-31 October 2003 we observed on the territory of Northern America. It should be noted that GPS positioning errors increased significantly not only within auroral area but also in the south- west of Northern America, at low enough latitudes (30-350 N; 240- 2550 E). High absolute values and steep TEC gradients were observed in this region concurrently. TEC variations intensity in the period range of 1-10 min increases by one order as intensive LS AGW propagates from the northeast to the southwest of the USA. Space-time characteristics of GPS positioning errors are close to the corresponding intensity characteristics of small-scale irregularities. It is in accord with the existing idea that phase slips are caused by GPS radio signals scattering on small-scale irregularities.